South Korea's Navy will arm its latest frigates with tactical missiles that can strike deep into North Korea, a military source said Sunday.

The plan calls for arming the Incheon-class ships with land-attack missiles that have a range of 150-200 kilometers. The missiles, to be loaded onto the ships starting in September, will allow the frigates the ability to attack key targets in the communist country's interior from the sea.

"Initially, the plan was to arm batch 2 Incheon-class ships with the tactical missiles, but the government, after conducting feasibility studies, decided to retrofit the batch 1 ships," the official, who declined to be identified, said. The missiles will be housed in angled canister launchers on deck.

The first batch consisting of six frigates have an empty displacement of some 2,300 tons and were launched starting in 2011. The sixth and last frigate of batch 1 is undergoing sea trials and will join the fleet early next year. The second batch of ships will be heavier with an empty displacement of 2,800 tons.

The frigates that are replacing the aging Ulsan-class frigates and Pohang-class corvettes have a 127-millimeter main gun with point defense being handled by the 20 mm Phalanx system. It also has Rolling Airframe Missiles, or RAMs, for short-range anti-aircraft defense and employs SSM-700K to deal with surface threats as well as torpedoes to destroy submarines.

The decision to arm the relatively small coastal defense ships with tactical missiles comes as Seoul is moving to give the Navy greater flexibility not only to engage enemy ships but also to respond to diverse threats.

"The tactical missiles will greatly enhance the combined fighting ability of South Korea's armed forces and add another layer of deterrence against North Korean aggression," he said.

South Korea has already been arming its tactical land-attack missiles on its larger destroyers to take out key North Korean targets in case of conflict. It has, moreover, been moving to upgrade the fighting capability of existing ships with new weapons systems.

The Navy said it plans to deploy short-range anti-aircraft missiles with a range of 20 km on its latest patrol boats that are already armed with anti-ship missiles. (Yonhap)